It was found that hog kidney mutarotase has an affinity for Sephadex G-100, equilibrated and eluted with 5 mmol/l EDTA buffer (pH 7.4), resulting in retardation of its elution from the column. The affinity was reduced depending upon the presence of 0.15 mol/l NaCl and 0.2 mol/l glucose, separately or in combination. A small portion of mutarotase was adsorbed to rabbit liver glycogen as judged from the column chromatography of a mixture of the two on Bio-Gel P-100. Mutarotase was adsorbed to neither dextran nor raw potato starch.